Magnetic lock and wrench

ABSTRACT

A magnetic lock and wrench, particularly adapted for fire hydrants in which one of the members of the lock, namely, the inner member is secured to the lug of the fire hydrant, with the outer member positioned thereover and rotatable relative thereto when in an unlocked position, and coupling means therebetween operated by a wrench having magnetic means which when applied to the outer member will cause the coupling means to couple the inner and outer members so that rotation of the outer member by the wrench will rotate the inner member and the fire hydrant lug to open and close the fire hydrant valve and/or like member.

United States Patent [191 McMurray 11] 3,840,041 [451 Oct. 8, 1974 MAGNETIC LOCK AND WRENCH Primary Examiner- -Alan Cohan Assistant Examiner-Richard Gerard 76 Inventor: Bud A. McMurra 923 Wa ne l 1 Ave" Deemeld, 60607 y Attorney, Agent, or Firm-Max R. Kraus [22] Filed: Jan. 25, 1971 [57] ABSTRACT [21] Appl. No.: 109,248 I A magnetic lock and wrench, particularly adapted for fire hydrants in which one of the members of the lock, [52] U.S. Cl. 137/296, 81/90 C, 137/382, namely the inner member is Secured to the lug of the 192/84 PM, 192/ 108, 251/65, 251/89, 251/291 fire hydrant, with the outer member positioned there- [51] 111i. Cl. Flok 35/06 over and rotatable relative thereto when in an [58] held of Search !92/84 251/65, locked position, and coupling means therebetween op- 251/89, 137/272 382 erated by a wrench having magnetic means which when applied to the outer member will cause the cou- [56] References and pling means to couple the inner and outer members so UNITED STATES PATENTS that rotation of the outer member by the wrench will 2,389,461 11/1945 Satterlee 192/84 C X rotate the inner member and the fire hydrant lug to 3,176,531 4/1965 Plume 192/84 AA X open and close the tire hydrant valve and/or like 3,453,897 7/1969 Adinolfi 251/291 X member. 3,556,131 l/l97l Diaz 251/291 X 9 Claims, 6 Drawing Figures 79 o w 78 v c 60 76 70 I, jIl/l/ll lllllllllllllllllll N W l. 52 g8 26 Il HQ 27 |& 56 14 4s PATENTEU 8 I974 sum HP 2 FIG. 1

PEG. 2

BUD A. McMURRAY ATTYS- PAIENEuum 81974 SHEEF 2 OF 2 lnvenior BUD A. McMURRAY 'ATTYS.

I MAGNETIC LOCK AND WRENCH BRIEF SUMMARY OF THE INVENTION It is well recognized, particularly in connection with fire hydrants, that the unauthorized opening of the valve will result in a tremendous waste of water, as well as other objectionable results, all of which are well known. One of the objects of this invention is to provide a device which is readily attachable to the lug of a standard fire hydrant which will not operate to either open or close the fire hydrant valve unless a wrench having magnetic properties is applied, which wrench would be in the possession of authorized personnel, such as members of the fire department or others who are authorized to open and/or close fire hydrants.

The lock includes an inner member which is attached to the fire hydrant lug, an outer member, and coupling means therebetween, with the coupling means movable into coupling position when a wrench having magnetic means is applied to the outer member so that rotation of the outer member will rotate the inner member and with it the fire hydrant lug to open or close the fire hydrant valve. In the absence of the application of the magnetic wrench, the coupling means will remain in uncoupled position and no rotation can be imparted to the inner member and the fire hydrant valve will remain unaffected.

Other objects will become apparent as this description progresses.

I BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a view of my invention applied to a fire hydrant.

FIG. 2 is an exploded view of certain of the components forming this invention.

FIG. 3 is a sectional view taken on line 33 of FIG.

FIG. 4 is a sectional view similar to FIG. 3, but with the magnetic wrench applied to couple the cooperating parts to operate the fire hydrant valve.

FIG. 5 is a sectional view taken on line 5-5 of FIG. 3, and

FIG. 6 is a view partly in section of the magnetic wrench.

While the lock is described in relation to a fire hydrant it is not limited thereto as it may be used in connection with other valve means which may be similarly.

operated.

The conventional fire hydrant 10 has a standard lug or head 12 which in most instances is five-sided or of pentagon shape and is exposed to be normally engaged by a conventional wrench so that the lug is rotated to open and close the fire hydrant valve. In some instances the lug may be of square shape. The present invention is directed to means which are secured to said lug 12 to rotate same when it is done by authorized personnel who have the special magnetic wrench.

The invention includes an inner member or a lock base generally indicated by the numeral 14 and an outer member or lock cap generally indicated by the numeral 16 and locking or coupling pins 18 positioned therebetween, which locking pins are moved into coupling position to couple the inner and outer members 14 and 16 respectively when a wrench, generally indicated at 20, having magnetic properties is applied to the outer member 16 to rotate same. The foregoing is a general description of the operating elements which will now be described in greater detail.

The inner member or lock base 14 can be either a machined casting or machine part of some nonmagnetic metal, such as bronze. It is of cylindrical shape and is provided with a hollow lower portion 22, the interior of which has five sides or is of pentagon shape as indicated by the numeral 23. The upper end of the inner member or lock base 14 has a horizontal top wall surface 24 which is provided with four holes or recesses 26 which are located 90 apart, and these holes or recesses are adjacent the outer circumference of the top wall surface 24. They are preferably drilled but may be otherwise formed and they extend perpendicular to the top surface. The upper edge of each of these holes is chamfered as at 27 and the bottom of said hole slopes downwardly as at 28 towards the axis of said hole. These holes or recesses serve to receive the locking or coupling pins 18, which pins serve to couple and uncouple the outer member 16 with respect to the inner member 14.

A central vertical bore or opening 30 is provided to extend through the top wall 24 and said bore communicates with an enlarged annular recess 32, which in turn communicates with the interior 22 of the inner member 14. The lower outer portion 34 of the inner member or lock base 14 is of a reduced diameter for a portion of its height, whereas the outer portion 35 extending upwardly thereof to the top is of a larger diameter. The lower portion 34 is provided with a plurality of equally spaced transversely extending internally threaded holes 36 which extend into the interior 22 of the inner member or lock base 14. The hole is countersunk as at 37. An annular groove 38 is formed on the outer surface of the upper portion 35, of the lock base 14 to accommodate a sealing O-ring 39.

The inner member or lock base 14 is adapted to be positioned on the fivesided conventional fire hydrant lug 12, with the inside five-sided wall 23 of the inner member or lock base 14 loosely engaging the sides of the fire hydrant lug 12. The inner member or look base 14 is secured to the fire hydrant lug 12 by means of set screws 40 (FIG. 5) passing through said transversely extending openings 36, with said set screws engaging the five sides of the lug 12 of the fire hydrant. The set screws 40 which are threaded into the transversely extending openings 36 in the inner member or lock base 14 are of a material such as steel and of a length adequate to extend through the lower portion of the lock base, and of a diameter sufficient to provide the necessary strength to resist the removal of the device by methods other than the one provided for in its design. The outer end or head 41 of the set screw is accommodated in the countersunk portion 37 and the interior of the head and has a five-sided indentation 42 to accommodate the installation key 44.

The outer member or lock cap, generally indicated by the numeral 16, can be a machined casting or a machined part formed of a non-magnetic metal, such as bronze. It is cylindrical in shape and has an annular wall 46 which provides a hollow lower portion 48. The upper end of the lock cap 16 is closed by a horizontally extending top wall 50, which top wall is of a suitable thickness to accommodate four equally spaced holes or recesses 52 located on the underside of the top wall 50, which holes or recesses are in alinement with the holes 26 in the top surface of the inner member or lock base 14. The holes 52 do not extend through the closed top wall 50. The holes 52 serve to accommodate a portion of the coupling pins 18 when the pins are magnetically attracted to the magnetic wrench, as shown in FIG. 4, and as will be subsequently described.

The locking or coupling pins 18 are cylindrical in shape, solid and flat on each of its opposite ends, with the top and bottom edges slightly chamfered, as best seen in FIGS. 3 and 4. They are of a material such as hardened steel, which is subject to magnetic force. These locking pins are of a size to provide a loose fit in the holes or recesses 26 and 52. The locking pins 18, therefore, are of a smaller diameter than the diameter of the holes or recesses.

When the locking or coupling pins 18 move upwardly into the holes or recesses 52 in the outer member 16, the lower portion of said pins will be in engagement with the holes or recesses 26 in the inner member 14 and thus when in such position will couple the outer member 16 to the inner member 14 to lock them together for simultaneous rotation. However, when there is no magnetic wrench applied to the outer member, as shown in FIG. 3, then the coupling pins 18 will be located in the holes 26 of the inner member 14 and the inner and outer members 14 and 16 respectively, will be uncoupled so that rotation of the outer member 16 will not impart a corresponding rotation to the inner member 14.

The inside diameter of the wall 46 of the outer member 16 is slightly larger than the outside diameter of the exterior wall 35 of the inner member or lock base 14. The sealing O-ring 39 is of a soft, pliable and weatherproof material, such as neophrene, and of a diameter to provide a tight fit in the groove around the upper portion of the inner member 14 and of a thickness to provide a tight seal between the inner member 14 and outer member 16.

The outer member or lock cap 16 is centrally provided with an annular depending projection or stem 54 which extends downwardly from the center of the underside of the top wall 50 and is received in the central bore 30 of the inner member 14. The stem has an internally threaded bore 56 to accommodate a threaded screw 57, the head of which engages a washer 58 which rests against a shoulder 59 formed by the enlarged recess 32. The screw and washer are made preferably of steel and are of a size to provide sufficient strength to hold the inner member to the outer member. By this means the outer member or lock cap 16 is connected to the inner member or lock base 14 and this permits the outer member 16 to be rotated relative to the inner member 14 without disengaging or separating them.

Extending centrally upwardly of the top wall 50 of the outer member 16 is a five-sided lug or head 60 which is adapted to be engaged by the wrench 20, to be subsequently described. A vertically extending slot 62 is provided at the bottom of the annular wall 46 of the outer member 16 to allow the installation key 44 to be slid up and engage the heads of the set screws 40 on the inner member or lock base 14 when the lock base is initially installed on a fire hydrant lug or, if necessary, to remove it therefrom. The installation key 44, as best seen in F IG. 5, has a reduced annular portion 45 which permits the key to be inserted from the bottom of the vertical slot 62 as well as the vertical slot in the skirt,

to be described, so that the key can engage the set screws 40 to rotate same.

The outer member or lock cap 16 has an annular groove 64. Positioned around the exterior of the outer member 16 is a cylindrical skirt or shell 66 having an inwardly extending lip or flange 68 which rides within the annular groove 64. The bottom of the skirt is provided with a vertically extending slot 69. Said cylindrical skirt is rotatable relative to said outer member 16 to prevent any unauthorized person from applying any wrench to the cylindrical exterior of the outer member or lock cap 16. If an unauthorized wrench were applied to engage the skirt 66 on the outer member, the outer member 16 could not be manually rotated by said wrench by virtue of the loose skirt with which the wrench would come into engagement and rotation of the skirt by said unauthorized wrench would still not rotate the outer member 16.

As is clear from the foregoing description, the lock cap or outer member 16 is placed over the inner member or lock base 14, with the stem 54 projecting into the bore 30 in the center of the inner member or lock base and the two are connected together by means of the screw 57 and washer 58. With the coupling pins 18 resting within the holes 26 of the inner member 14, the outer member 16 may be rotated relative to the inner member 14 without rotating the lug 12 of the fire hydrant.

The specially constructed wrench for operating this device is generally indicated at 20 and comprises a head 70 made of cast iron or other suitable material having an annular opening 72 extending through the thickness of the head which receives an Alnico magnet 74. The Alnico magnet is provided with a five-sided central opening 76. A handle 78, preferably of steel, to be manually engaged, has a threaded end 79 which engages an internally threaded transversely extending bore 80 in the head 70. The magnet is also provided with a transversely extending bore 82 which is alined with the bore 80 to receive the end 79 of the handle to thus securely lock the magnet to the head of the wrench. The five-sided opening 76 in the magnet is slightly larger than the dimension of the standard fire hydrant lug 12. The magnet 74 is of a diameter equal to the diameter of the top of the outer member or lock cap 16 so that when the wrench is positioned on the lug or head 60 of the outer member or lock cap, the magnet 74 will be adjacent the top of the lock cap and will be in alinement with the locking pins 18 to attract and draw them upwardly. The magnet is of a thickness of that of the head 70 of the wrench so that whichever side of the head is applied to the top of the lock cap there will be sufficient magnetic force to attract the locking pins 18.

As can be understood from the foregoing description, the installation key 44 is an Allen-type wrench having five sides instead of the standard six sides and the installation key has a reduced cylindrical portion 45 which slides into the slot 62 of the outer member 16 and the slot 69 of the skirt 66 when the corresponding slots 62 and 69 are alined. Transversely extending indentations or recesses 84 are formed in the sides of the standard lug 12 of the fire hydrant to be engaged by the screws 40 to lock the inner member or lock base 14 to the lug 12 of the hydrant and said screws are tightened by the Allen-type wrench 44, best shown in FIG. 5, to

secure the inner member or lock base to the lug of the fire hydrant.

OPERATION The wrench is placed on the lug or head 60 of the outer member or lock cap 16 so that the five-sided opening 76 of the magnet 74 surrounds the five-sided head 60 of the outer member 16. The surface of the magnet will be positioned adjacent the top wall of the outer member 16. The magnet 74 will attract and pull up the locking pins 18 from the position shown in FIG. 3 to the up position shown in FIG. 4, where the locking pins 18 couple the inner and outer members 14 and 16 to establish a solid connection therebetween. When the wrench is manually rotated, rotating the outer member 16, it will then simultaneously rotate the inner member 14 which is secured to the lug 12 of the fire hydrant and thus turn the lug 12 of the fire hydrant to open or close the valve of the fire hydrant. When the wrench 20 is removed from the top wall 50 of the outer member the locking pins 18 fall back into the recesses 26 of the lock base or inner member 14 and the lock cap 16 can then be turned freely relative to the lock base 14 without rotating the lock base 14.

It should be noted that before the locking pins 18 can move into the up position of FIG. 4, the outer member 16 must first be rotated by the wrench so that the recesses 52 in the outer member 16 are in alinement or registry with the recesses 26 in the inner member 14, for unless they are in registry the locking pins 18 cannot move into the recesses 52 in the outer member 16 to couple the two members to impart a rotation to the inner member 14.

Once the wrench is applied to the head the pins 18 will move into coupling position with hole 52 when the outer member is rotated so that the holes 52 register with holes 26. In other words, coupling takes place automatically when the magnet of the wrench pulls the pins 18 upwardly as the holes pass over the holes 26.

The rotatable skirt 66 serves to make the device foolproof in that the outer member 16 cannot be rotated by engaging the cylindrical wall of the outer member with a wrench and using a conventional magnet to move up the locking pins 18 to coupling position. A wrench 20 like that described must be used for operating the device.

What is claimed is:

1. In a device for opening and closing a valve, said device comprising an inner member adapted to be at-l tached to a valve operating member, said inner member having a hollow interior corresponding to the shape of the valve operating member so that said inner member may be secured to said valve operating member, an outer member adapted to fit over said inner member, said inner and outer members each having recesses, coupling means comprising locking pins between said inner and outer members and adapted to normally be positioned in said recesses of said inner member to permit said outer member to be rotated relative to said inner member without imparting a corresponding rotation to the inner member, and magnetic means adapted when positioned relative to said outer member tocause said coupling means to move into engagement with the recesses in said outer member while remaining in engagement with the recesses in said inner member to couple said outer and inner members so, that when said outer member is rotated a corresponding rotation will be imparted to said inner member to rotate the valve operating member for opening and/or closing a valve, said coupling means adapted when the magnetic means is removed to be moved entirely into the recesses in said inner member to uncouple the outer and inner members to permit said outer member to be rotated relative to said inner member without a corresponding rotation of said inner member.

2. A structure as set forth in claim 1 in which the inner member is adapted to be secured to a lug operating a valve of a fire hydrant so that when the outer member is rotated and the coupling means are in position to couple the outer and inner members a corresponding rotation will be imparted to the lug of the fire hydrant to open or close the valve of the fire hydrant.

3. A structure as set forth in claim 2 in which a skirt is rotatably supported on said outer member so that said skirt is rotatable at all times relative to said outer member without imparting a rotation to said outer member.

4. A structure as set forth in claim 1 in which the inner member has means for locking same to a fire hydrant lug, operating a valve of a fire hydrant.

5. A structure as set forth in claim 1 in which the inner member has a central opening and in which the outer member has a central projection extending into said central opening, and means for securing said outer and inner members relative to each other to prevent separation therebetween but permitting relative rotation therebetween when said coupling means are in uncoupled position. v

6. A structure as set forth in claim 1 in which the magnetic means is part of a wrench which wrench cooperates with a lug of the outer member to rotate said outer member but no corresponding rotation is imparted to said inner member unless said coupling means are magnetically attracted to couple the inner and outer members.

7. In a device for opening and closing a valve, said device comprising an inner member adapted to be attached to a valve operating member, an outer member, coupling means between said inner and outer members and adapted to normally be positioned to permit said outer member to be rotated relative to the inner member without imparting a corresponding rotation to the inner member, and magnetic means adapted when positioned relative to said outer member to cause said coupling means to couple said outer and inner members so that when said outer member is rotated a corre-- sponding rotation will be imparted to said inner member to rotate the valve operating member for opening and/or closing a valve, said magnetic means being part of a wrench head which is applied to the outer member for rotating same, and in which thethickness of the magnetic means is substantially that of the wrench head so that the wrench head may be applied with either side adjacent the top of the outer member for magnetic attraction of the coupling means.

8. In a device for opening and closing a valve, said device comprising an inner member having an internal surface corresponding to the shape of a lug operating a valve of a fire hydrant, said inner member adapted to be attached to said fire hydrant lug, an outer member adapted to be positioned over said inner member but rotatably secured with respect thereto, coupling means outer member is rotated a corresponding rotation will be imparted to said inner member to rotate the fire hydrant lug for opening and/or closing a valve.

9. In a device for attachment to a lug for operating a valve of a fire hydrant, said device comprising an inner member having an interior shape complementary to the shape of the fire hydrant lug and adapted to be attached to said fire hydrant lug, an outer member positioned over said inner member, said outer member having a head corresponding in shape to the shape of the fire hydrant lug, coupling means between said inner and outer members and adapted to normally be positioned to permit said outer member to be rotated relative to the inner member without imparting a corresponding rotation to the inner member, and magnetic means comprising a wrench having a magnetic element, said magnetic element having an opening corresponding in shape to that of the head of said outer member to be accommodated on the head of said outer member and when positioned thereon adapted to attract the coupling means to couple said outer and inner members so that when said wrench rotates said outer member, said inner member will be correspondingly rotated and when said wrench is removed said coupling means will drop by gravity into said inner member to uncouple the outer and inner members relative to each other. 

1. In a device for opening and closing a valve, said device comprising an inner member adapted to be attached to a valve operating member, said inner member having a hollow interior corresponding to the shape of the valve operating member so that said inner member may be secured to said valve operating member, an outer member adapted to fit over said inner member, said inner and outer members each having recesses, coupling means comprising locking pins between said inner and outer members and adapted to normally be positioned in said recesses of said inner member to permit said outer member to be rotated relative to said inner member without imparting a corresponding rotation to the inner member, and magnetic means adapted when positioned relative to said outer member to cause said coupling means to move into engagement with the recesses in said outer member while remaining in engagement with the recesses in said inner member to couple said outer and inner members so that when said outer member is rotated a corresponding rotation will be imparted to said inner member to rotate the valve operating member for opening and/or closing a valve, said coupling means adapted when the magnetic means is removed to be moved entirely into the recesses in said inner member to uncouple the outer and inner members to permit said outer member to be rotated relative to said inner member without a corresponding rotation of said inner member.
 2. A structure as set forth in claim 1 in which the inner member is adapted to be secured to a lug operating a valve of a fire hydrant so that when the outer member is rotated and the coupling means are in position to couple the outer and inner members a corresponding rotation will be imparted to the lug of the fire hydrant to open or close the valve of the fire hydrant.
 3. A structure as set forth in claim 2 in which a skirt is rotatably supported on said outer member so that said skirt is rotatable at all times relative to said outer member without imparting a rotation to said outer member.
 4. A structure as set forth in claim 1 in which the inner member has means for locking same to a fire hydrant lug, operating a valve of a fire hydrant.
 5. A structure as set forth in claim 1 in which the inner member has a central opening and in which the outer member has a central projection extending into said central opening, and means for securing said outer and inner members relative to each other to prevent separation therebetween but permitting relative rotation therebetween when said coupling means are in uncoupled position.
 6. A structure as set forth in claim 1 in which the magnetic means is part of a wrench which wrench cooperates with a lug of the outer member to rotate said outer member but no corresponding rotation is imparted to said inner member unless said coupling means are magnetically attracted to couple the inner and outer members.
 7. In a device for opening and closing a valve, said device comprising an inner member adapted to be attached to a valve operating member, an outer member, coupling means between said inner and outer members and adapted to normally be positioneD to permit said outer member to be rotated relative to the inner member without imparting a corresponding rotation to the inner member, and magnetic means adapted when positioned relative to said outer member to cause said coupling means to couple said outer and inner members so that when said outer member is rotated a corresponding rotation will be imparted to said inner member to rotate the valve operating member for opening and/or closing a valve, said magnetic means being part of a wrench head which is applied to the outer member for rotating same, and in which the thickness of the magnetic means is substantially that of the wrench head so that the wrench head may be applied with either side adjacent the top of the outer member for magnetic attraction of the coupling means.
 8. In a device for opening and closing a valve, said device comprising an inner member having an internal surface corresponding to the shape of a lug operating a valve of a fire hydrant, said inner member adapted to be attached to said fire hydrant lug, an outer member adapted to be positioned over said inner member but rotatably secured with respect thereto, coupling means comprising a plurality of locking pins between said inner and outer members and adapted to be normally supported on said inner member in uncoupled relation to said outer member to permit said outer member to be rotated relative to the inner member without imparting a corresponding rotation to the inner member, and magnetic means adapted when positioned relative to said outer member to cause said coupling means to couple said outer and inner members so that when said outer member is rotated a corresponding rotation will be imparted to said inner member to rotate the fire hydrant lug for opening and/or closing a valve.
 9. In a device for attachment to a lug for operating a valve of a fire hydrant, said device comprising an inner member having an interior shape complementary to the shape of the fire hydrant lug and adapted to be attached to said fire hydrant lug, an outer member positioned over said inner member, said outer member having a head corresponding in shape to the shape of the fire hydrant lug, coupling means between said inner and outer members and adapted to normally be positioned to permit said outer member to be rotated relative to the inner member without imparting a corresponding rotation to the inner member, and magnetic means comprising a wrench having a magnetic element, said magnetic element having an opening corresponding in shape to that of the head of said outer member to be accommodated on the head of said outer member and when positioned thereon adapted to attract the coupling means to couple said outer and inner members so that when said wrench rotates said outer member, said inner member will be correspondingly rotated and when said wrench is removed said coupling means will drop by gravity into said inner member to uncouple the outer and inner members relative to each other. 